Device for transforming oscillating movement into rotary movement

ABSTRACT

A device for transforming oscillating movement into rotary movement includes a flexible blade fixed at one end and carrying a pawl in driving engagement with a ratchet wheel at its other free end. Between its ends, the blade has a bent or curved portion and a bearing piece acts on the blade between its bent portion and its fixed end. This bearing piece transforms the oscillating movement of a driving member into an unilateral pressure on the blade, which flexes the blade and causes the pawl to drive the ratchet wheel. To prevent reversal of the ratchet wheel, a retaining pawl can be provided; alternatively two bent flexible blades each carrying a driving pawl may be driven in phase opposition.

United States Patent Challandes June 18, 1974 DEVICE FOR TRANSFORMINGOSCILLATING MOVEMENT INTO ROTARY MOVEMENT [75] Inventor: ClaudeChallandes,Sonceboz, Switzerland [73] Assignees: Montres Rolex S.A.,Geneva; V

Manufacture des Rolex S.A., Bienne; Societe anonyme de la fabriquedhorlogerie Le Coultre & Cie, Le Sentier, all of, Switzerland 22 Filed:Nov. 14,1972

[21] Appl. No: 306,405

[30] Foreign Application Priority Data Nov. 15, 1971 Switzerland16551/71 [52] US. Cl. 74/142, 74/128 [51] Int. Cl. Fl6h-27/02 [58] Fieldof Search 74/142, 128, 575, 577

[56] References Cited UNlTED STATES PATENTS 1,632,405 6/1927 Harrison74/143 2,868,026 1/1959 Finehout et al 74/142 3,204,133 8/1965 Tshudin74/142 3,489,024 l/1970 Ramsetter 74/142 5 7] ABSTRACT A device fortransforming oscillating movement into rotary movement includes aflexible blade fixed at one end and carrying a pawl in drivingengagement with a ratchet wheel at its other free end. Between its ends,the blade has a bent or curved portion and a bearing piece acts on theblade between its bent portion and its fixed end. This bearing piecetransforms the oscillating movement of a driving member into anunilateral pressure on the blade, which flexes the blade and causes thepawl to drive the ratchet wheel. To prevent reversal of the ratchetwheel, a retaining pawl can be provided; alternatively two bent flexibleblades each carrying a driving pawl may be driven in phase opposi tion.

4 Claims, 12 Drawing Figures PATENTEDJun 18 m4 sum u or 5 Fig. 1a

PATENTI'IBJ sum 5 er 5,

MOVEMENT OF 757' PAWL MOVEMENT 0F ZNOIPAWL Flg.11

DEVICE FOR TRANSFORMING OSCILLATING MOVEMENT INTO ROTARY MOVEMENT Theinvention relates to devices for transforming oscillating movement intorotary movement and is particularly concerned with devices fortransforming the oscillating movement of a driving member into a rotarymovement of a toothed wheel by means of at least one driving pawl on theend of a blade.

Swiss Pat. No. 497,725 (Straumann) describes (with reference to FIG. 1of its drawings) a device for transforming a rotary movement into aslower rotary movement by means of a bent blade. The rotary movement tobe transformed is transmitted to the blade by means of an eccentricdisposed in the proximity of the bent part of the blade. The eccentricdrives the blade with an oscillating movement causing a toothed wheel tobe turned around. Turning of the wheel is thus caused by the movementproduced by the eccentric and transmitted to the toothed wheel via theblade.

An object of the invention is to provide a device for transforming anoscillating movement into a rotary movement by means of a pawl-carryingflexible blade by using the property of resilient flexibility of theblade to drive a toothed wheel.

The device according to the invention is characterised in that thisblade includes a bent portion, the end of the blade opposite to thepawl-carrying end being fixed. The driving member transmits its movementvia a bearing part exerting an unilateral pressure on the blade betweenthe support and the bent portion to produce flexion of the blade.

The term bent portion is herein used to designate not only abruptelbow-like bent portions, but also curved or bowed portions.

Three embodiments of the invention will now be described, by way ofexample, with reference to the accompanying schematic drawings, inwhich:

FIG. 1 shows a bent blade for transmitting the oscillating movement of aresonator to a mobile or driving pawl;

FIGS. 2 and 3 are explanatory graphs illustrating the operation of theblade of FIG. 1;

FIG. 4 is a plan view of a first embodiment of device according to theinvention, this device including a pawl-carrying blade similar to thatof FIG. 1;

FIG. 5 is an enlarged scale view showing several teeth of the ratchetwheel of FIG. 4;

FIG. 6 is a graph showing the operative driving range of the singledriving pawl of the device of FIG. 4;

FIG. 7 is a plan view of a second embodiment of device according to theinvention for transforming an oscillating movement of relatively largeamplitude into a rotary movement;

FIG. 8 is a graph explaining the operation of the device of FIG. 7;

FIG. 9 is a view of a detail showing means for limiting the lateralmovement of a pawl;

FIG. 10 is a plan view of a third embodiment of device according to theinvention for transforming the movement in phase opposition of two armsof a resonator into a rotary movement;

FIG. 1 1 is an explanatory graph for the device of FIG. 10; and

FIG. 12 shows a mechanism for setting the phase of the pawls of thedevice of FIG. l0.

The flexible blade 1 shown in FIG. 1 is bent with a certain angle a andone of its ends is solidly secured to a fixed support 2 by being set orembedded therein. Its other free end B carries a pawl which moves over asurface 3 corresponding to the tangent to a toothed wheel at the pointof contact of the pawl therewith. The movement from A to A of a pin 4acting on the blade 1 causes a displacement D of the end E of the bladeto E. Displacement of the blade from A to A takes place over a distancef called the deflection, and the blade is divided into three segments oflength l l and 1 as shown in FIG. 1.

The displacement D of the end of the blade depends not only on thedeflexion f but also upon the parameters a, l l and 1 For given lengthsl l and 1 a family of curves of the displacement D as a function of thedeflexion f is obtained for various angles at. These curves are shown inFIG. 2 for three angles or a a The .force F that the pin 4 must exert toproduce deflexion f also depends upon the geometrical disposition andupon the rigidity of blade 1.

Referring to FIG. 3, let us now consider a small amplitude sinusoidalmovement of the pin 4 superimposed on the means deflexion fin,considered as a tensioning or bracing. A given point-to-point path oramplitude C of the end of pin 4 corresponds to a path or amplitude C ofthe end E of blade 1, which is a function of the mean tension ordeflexion f (curve D (f) of FIG. 3). The ratio C /C is the slope of thetangent T of curve a in FIG. 3 at the working point. By suitablyselecting the values of 01, 1 ,1 and fm, it is thus possible to pro ducean amplification or a reduction (attenuation) of the amplitude of themovement.

This principle is applied for transforming the vibratory movement of aresonator into a rotary movement. A device provided for this purpose isshown in FIG. 4 and comprises a bent blade 5 similar to the blade ofFIG. 1. One of the ends of blade 5 is firmly secured at 6 to a fixedsupport by being set or embedded therein, and the other free end carriesa pawl 12 bearing against a toothed wheel 7 the very fine teeth of whichare not shown in FIG. 4. A pin 8 connected to an arm 9 of a resonatorbears perpendicularly against the blade 5 and transmits to pawl 12 thevibratory movement of the resonator arm 9, as indicated by the doubleheaded arrow. The pin 8 acts on the substantially rectilinear part ofblade 5 located between its point of fixation and the bent part,preferably near to the bent part. An end 11 of a substantiallyrectilinear second flexible blade 10 is finnly secured to the fixedsupport, and its other free end carries a retaining pawl 13 which alsocontacts the teeth of wheel 7. The two pawls are in phase when at restthe distance separating them is equal to (n MP, where n is a wholenumber and P is the pitch of the teeth of wheel 7 (FIG. 5). Theresonator drives the ratchet wheel 7 by means of pawl 12.

It is clear that blade 5 could, instead of having a sharp bend as shownin FIG. 4, have a smooth curvature or bowed part near its pawl-carryingend. In such a variation, not shown, the blade has a straight partadjacent its fixed end followed by a curved part extending from thepoint of action of pin 8 to the free end carrying pawl 12. Theexplanations given in relation to FIGS. 2 and 3 remain valable for acurved blade, and in this case the angle a is the angle formed between atangent to the free end of the blade and a perpendicular to the straightpart of the blade. Also the blade 5 could, in a limiting case, be curvedor bowed from end to end, for example in the shape of an arc of acircle.

Moreover, the blade could be secured to the support by means of a pivot.

The operating conditions for the pawl-and-ratchet drive are shown inFIG. 6. The pawl 12 moves with a periodic movement represented by thesinusoidal curve D(t) centred about the mean value D,, and whosepoint-to-point travel or amplitude is C The conditions to be fulfilledfor the pawl 12 to drive wheel 7 by only one tooth per period aredefined by the extreme positions of the pawl. In its forward movement(considering the direction of rotation of wheel 7 indicated by the arrowin FIG. 4), the pawl 12 reaches an extreme position D, k C It drives thewheel and the fixed or retaining pawl 13 jumps from one tooth to thefollowing at the ordinate Da If pawl 12 moves further, the wheel 7 wouldbe rotated by a greater amount and, at D113, the pawl 13 would jump asecond tooth. The extreme forward position of the pawl 12 must thus becomprised between Da and D11 preferably in the neighborhood of the meanordinate Da In its rearward movement, pawl 12 drives the wheel 7 in thereverse direction until one of the teeth of wheel 7 comes to abutagainst pawl 13. Then, the wheel 7 is fixed and the driving pawl 12slips over a tooth until it jumps to the following tooth at ordinate DrIf pawl 12 continues to move back, it will jump over a second tooth atDr;,. The extreme rearward position of pawl 12 must thus be comprisedbetween Dr, and Dr;,, preferably near to the mean ordinate DrConsequently, the best operation corresponds to a mean position D ofpawl 12 coinciding with the ordinate D centred in relation to Da and Drand which will be designated by the term zero phase, and with the path Cof pawl 12 equal to twice the pitch P of the teeth of wheel 7. In theseconditions, the greatest possible safety margin is provided concerningpossible deviations in the phase D,, or the path C For example, if theamplitude is correct, the phase may vary by nearly P without causing anirregularity in the drive. If the phase is correct, the path C may varyfrom a minimum slightly above P to a maximum nearly up to 3 P. It isclear that by staggering or displacing all of these ordinates D by aphase corresponding to the pitch P or a multiple thereof, new equallyvalid limiting values will be obtained (see the right hand part of FIG.6).

These considerations show the importance of ensuring that the drivingpawl 12 has a well determined and constant phase and amplitude. An aimof the invention is to ensure that these conditions are fulfilled, evenif the movement of the driving member (resonator or pallet) is lessprecise and subject to unwanted variations, for example as a result ofshocks.

With use of a bent blade, several cases arise.

1. One Driving Pawl; One Fixed Pawl l.l Large Tensioning, SmallAmplitude In the graph of FIG. 3, the short portion of the curve aboutthe operating point can be approximated to a straight line. Thetransformation of movement between the driving pin and the end of thedriving pawl is thus linear and corresponds to a constant ratio C /CThis ratio can be modified by varying the mean tensioning or deflexion fAppropriate choice of the blade parameters (for the device of FIG. 4)enables the resonator amplitude at a given point to be adapted to thepitch of wheel 7, whatever be the point of fixation of the driving pin8. Great freedom in the construction is thus available since theresonator amplitude and the pitch P are independent.

Also, the pressure exerted by the pawl-carrying blade 5 on wheel 7varies during its movement. At the end of its path, pawl 12 passes froma forward to a rearward movement whilst exerting a high pressure on thewheel 7, and therefore tends to drive the wheel rearwardly, which isdesirable for correct operation. When the rearward movement of wheel 7is stopped by pawl 13, pawl 12 continues to move rearwardly whilstsliding over a tooth, then jumping to the next tooth. This slidinginvolves a loss of energy. It is thus advantageous that the end of therearward movement takes place at reduced pressure. The variation of thepressure exerted by pawl 12 thus favors a low power consumption.

The arrangement of FIG. 4 provides transmission of the movement in thedesired direction, as indicated by the double headed arrow. On thecontrary, any movement of the resonator in the two other directions(hori zontal lateral and perpendicular in relation to the drawing)produces a simple sliding of pin 8 on blade 5, without transmission ofthis movement to pawl 12. Such unwanted movements thus cause neither avariation in the phase of the pawls, nor a variation in the tensioningor deflexion of blade 5, nor a lateral displacement liable to move pawl12 out of the plane of wheel 7. This noncoupling in two directions is aninherent property of the device according to the invention andcontributes to its safety of operation by rendering it insensitive tovarious effects such as shocks and expansions. Moreover, it enables arelaxation of certain manufacturing tolerances and facilitates mounting.

1.2 Zero Tensioning, Large Amplitude This case (described with referenceto FIG. 7) is applicable to a wheel 7 having teeth of a sufficientlylarge pitch to enable advantage to be drawn from the nonlinearity of thecurves of FIG. 2. The movement of an oscillating member 31 istransmitted to a blade 5 carrying a driving pawl 12 by means of a bentpin 8 which, at rest, applies against blade 5 without deflecting it. Inthis example, the angle of bending of blade 5 is less pronounced thanfor that of FIG. 4. In its forward movement, the pin 8 moves pawl 12forwardly at first rapidly then progressively slower. During return, themovement takes place in the opposite direction, but as soon as the pin 8passes its rest position it moves away from blade 5 which stops alltransmission of movement. To avoid the pawl 12 from moving out ofengagement with wheel 7 during this phase, blade 5 may have a sufficienttension by a suitable inclination at its point of securing 6. It is alsopossible, as shown, to provide a pin 32 fixed on the support, this pinlimiting movement of blade 5 and precisely determining the position atwhich pin 8 moves away from blade 5. FIG. 8 shows a typical non-linearcharacteristic D (f) of this device, as well as the positions Da,, Da,,Da;,, Dr Dr Dr of the pawl as discussed in connection with FIG. 6. Tothese positions correspond deflexions on a non-linear scale, and evencertain ordinates such as fa fr and fr are inaccessible. Consequently,there is a considerable increase in the zones of correct opera tion. Itsuffices, in practice, to guarantee that during its movement pin 8advances beyond a first limit fa then moves back beyond a second limitfr By way of example, three periodic movements of the pin are shown at41, 42 and 43. The corresponding movements of pawl 12 are indicated bycurves 51, 52 and 53. Curve 41 corresponds to a movement of minimumamplitude compatible with a correct counting operation (regularoperation). Curve 42 corresponds to a mean amplitude, and curve 43 to alarge amplitude. It can be seen that the extreme positions of the pawlgiven by curves 51, 52, 53 vary but to a lesser degree. The device thusenables much larger tolerances in the mean phase and in the path(amplitude) of the driving member 31. It is also more resitant toshocks.

Although the devices of FIGS. 4 and 7 prevent any transmission to thepawl-carrying blade 5 of a movement of pin 8 perpendicular to the planeof these Figures, it is not impossible that a violent shock in thisdirection would directly act on either or both of pawls l2 and 13 andmake them move out of the plane of wheel 7. FIG. 9 shows a device foravoiding this, in which a pawl-forming stone 20 supported by a blade 21compelled to remain in the plane of a ratchet wheel 22 by means of twolimiting pieces 23 and 24 the facing surfaces of which are spaced aparton either side of the plane of wheel 22 and in the vicinity of thepawlforming stone 20.

2. Two Mobile Pawls In the embodiment of FIG. 10, two bent blades 25 and26 respectively carry two driving pawls 27 and 28 both in drivingengagement with a toothed wheel 14. The blades 25 and 26 arerespectively firmly supported at and 16 on a fixed support 17. Pins 18and 19 each connected to or mounted on an arm of a resonator (not shown)come to bear against the blades 25, 26 respectively in the proximity ofthe bent portions thereof.

The two arms of the resonator (not shown) oscillate is phase oppositionand each pin 18, 19 drives its respective pawl 27, 28 in the same manneras in the device of FIG. 4 with one bent blade. The device of FIG. 10 isadvantageous from the point of view of power consumption since the pathof the pawls is halved. Moreover, any phase error caused by asimultaneous movement of pins 18 and 19 in the same direction, as aresult of a shock for example, is practically totally excluded.

Curves 61 and 62 of FIG. 11 illustrate the movements of the two pins 18,19 during normal operation at a working point T and with a path oramplitude C Suppose that as a result of a shock, the two arms of theresonator are both displaced by an amount A in the same direction. Theresult of this is to displace the working point from T to T. If thedisplacement A is the same for the two blades, the resulting dephasingof their pawls is zero. The working point T is chosen so that the slopeC /C varies only slightly upon a displacement of the working point fromT to T. Consequently, the path or amplitude C of the pawls during thisdisplacement is close to the initial path C and the counting operation(i.e., regular running) is not disturbed. Phase Adjustment In all of theabove described arrangements, adjustment of the phase between the twopawls so that their separation corresponds to (n k) P is indispensableto obtain the indicated characteristics.

In conventional pawl and ratchet systems. the pawl is generally fixed onan element having a center of pivoting coinciding with the center of theratchet wheel, which enables modification of the phase of the pawlswithout altering the pressure with which they engage the wheel.

This principle is not applicable to the device according to theinvention, since displacement of the pawls about the wheel would modifythe tension of the driving pin against the pawl-carrying blade.

An arrangement which enables modification of the phase of the pawlswithout altering the pressure on the wheel and on the pin is shown inFIG. 12. In this phase adjusting mechanism, the blade 5 carrying anadjust able pawl 13 is fixed at 6 onto a resilient blade 71 firmly fixedat one end at 73 and bearing against a wedgelike member 72. A screw 74is adapted to bear against the other free end of blade 71 to enablemodification of the bowing thereof between its fixed end and member 72.The point 6 of securing blade 5 is preferably where the deflexion ofblade 71 is maximum dy/dx 0). Because of this, when the adjusting screw74 flexes blade 71, the pawl-carrying blade 5 moves in the direction ofarrow F, without changing its inclination relation to the point ofsecuring. This movement enables adjustment of the phase of the pawlswithout alteration of the pressure, since movement of blade 5 duringadjustment takes place (a) in the longitudinal direction of the substantially rectilinear part of blade 5 between point 6 and the bent portion,i.e., perpendicular to the direction of movement of the intermediarydriving piece, and (b) at least substantially parallel to the tangent towheel 7 at the point of contact of pawl 13. Also, by suitably choosingthe distance d in relation to the pitch of screw 74, an adequatesensitivity for carrying out adjustment will be obtained. An importantadvantage of this device is that adjustment of the phase can take placeduring operation of the resonator.

Advantages The advantages in relation to conventional devices of thedescribed devices with one bent blade are as follows:

Since the resonator and the bent blade are noncoupled, there is animprovement in the resistance to shocks in the two directionsperpendicular to movement of the driving pin.

Increase in the range of operation by provision of means fornon-linearly transforming movement be tween the resonator and and theratchet wheel, the results of which are reduction of the sensitivity toshocks in the direction of movement of the driving pin and increase inthe amplitude and phase tolerances.

Possibility of constructing a pawl and ratchet unit independent of theresonator.

The danger of dephasing due to play or relaxation (slackening) effectsis reduced, since the two pawls are secured on the same support.

Since forward movement of the wheel is produced by an elasticdeformation of the pawl-carrying blade, a part of the energy stored inthe blade is restituted during rearward movement of the driving pawl.

Possibility of amplification or attenuation of the ratio of amplitudebetween the resonator and the pawl for a given point of securing thedriving pin. This offers a great freedom in construction.

Ease of mounting, and reduction of the risks inherent during repairsince the pawls are not secured to the resonator.

The described device with two bent blades has the following additionaladvantages:

"Complete elimination of risks due to an identical displacement of thetwo arms of the resonator. Only a movement in phase opposition of thetwo arms is liable to effect regular running.

If shocks (angular and linear) cause no movement in phase opposition ofthe resonator arms they do not effect regular running.

Reduction of the power consumption.

What is claimed is:

1. Device for transforming an oscillating movement of a resonatordriving member comprising two arms oscillating in phase opposition intoa rotary movement of a toothed wheel, comprising two flexible bladeseach having a first end fixed to a support and a free second end, eachblade including a bent portion intermediate of said first and secondends and having a pawl at its free second end in driving engagement withsaid toothed wheel, said blades each cooperating with a respectivebearing piece formed by a pin on a respective one of said two armsbetween said fixed first end and said bent portion, said pins formingmeans for exerting an unilateral pressure on each blade to flex saidblades and drive said pawls in phase opposition.

2. Device according to claim 1, comprising means for adjusting thedistance between the points at which said first ends of said blades arefixed to said support.

3. Device according to claim 2, in which said adjusting means include aresilient elongate member having one end fixed to said support andanother free end, and screw means for resiliently displacing said freeend of the member, the first end of one of said blades being fixed tosaid member at a point such that when said free end of said member isdisplaced, said one blade is moved without rotation thereof along thedirection of a rectilinear part of said one blade between the first endand the bent portion thereof.

4. Device for transforming an oscillating movement of a driving memberinto a rotary movement of a toothed wheel, comprising at least oneflexible blade having a first end fixed to a support and a free secondend, said blade including a bent portion intermediate of said first andsecond ends, a pawl at said free second end of the blade, said pawldrivable engaging with said toothed wheel and disposed between a pair offacing surfaces spaced apart on either side of the plane of said toothedwheel, said surfaces forming means for limiting movement of said pawlout of said plane of said toothed wheel, and a bearing piece acted on bythe driving member and acting on the blade between said fixed first endand said bent portion, said bearing piece forming means for transformingoscillating movement of the driving member into an unilateral pressureon the blade to flex the blade.

1. Device for transforming an oscillating movement of a resonatordriving member comprising two arms oscillating in phase opposition intoa rotary movement of a toothed wheel, comprising two flexible bladeseach having a first end fixed to a support and a free second end, eachblade including a bent portion intermediate of said first and secondends and having a pawl at its free second end in driving engagement withsaid toothed wheel, said blades each cooperating with a respectivebearing piece formed by a pin on a respective one of said two armsbetween said fixed first end and said bent portion, said pins formingmeans for exerting an unilateral pressure on each blade to flex saidblades and drive said pawls in phase opposition.
 2. Device according toclaim 1, comprising means for adjusting the distance between the pointsat which said first ends of said blades are fixed to said support. 3.Device according to claim 2, in wHich said adjusting means include aresilient elongate member having one end fixed to said support andanother free end, and screw means for resiliently displacing said freeend of the member, the first end of one of said blades being fixed tosaid member at a point such that when said free end of said member isdisplaced, said one blade is moved without rotation thereof along thedirection of a rectilinear part of said one blade between the first endand the bent portion thereof.
 4. Device for transforming an oscillatingmovement of a driving member into a rotary movement of a toothed wheel,comprising at least one flexible blade having a first end fixed to asupport and a free second end, said blade including a bent portionintermediate of said first and second ends, a pawl at said free secondend of the blade, said pawl drivable engaging with said toothed wheeland disposed between a pair of facing surfaces spaced apart on eitherside of the plane of said toothed wheel, said surfaces forming means forlimiting movement of said pawl out of said plane of said toothed wheel,and a bearing piece acted on by the driving member and acting on theblade between said fixed first end and said bent portion, said bearingpiece forming means for transforming oscillating movement of the drivingmember into an unilateral pressure on the blade to flex the blade.